1.Structure a me ka hoʻomākaukau kumu o cellulose ether
Hōʻike ka Figure 1 i ke ʻano maʻamau o nā cellulose ethers. Hoʻololi kēlā me kēia bD-anhydroglucose (ka hui hou o cellulose) i hoʻokahi pūʻulu ma nā kūlana C (2), C (3) a me C (6), ʻo ia hoʻi, hiki i ʻekolu mau pūʻulu ether. Ma muli o ka intra-chain a me ke kaulahao hydrogen paʻa ocellulose macromolecules, he paʻakikī ke hoʻoheheʻe i ka wai a kokoke i nā mea hoʻoheheʻe organik. ʻO ka hoʻokomo ʻana o nā pūʻulu ether ma o ka etherification e hoʻopau i nā paʻa hydrogen intramolecular a intermolecular, hoʻomaikaʻi i kona hydrophilicity, a hoʻomaikaʻi nui i kona solubility i loko o ka media wai.
ʻO nā mea pani etherified maʻamau he mau pūʻulu alkoxy paona haʻahaʻa (1 a 4 mau kalapona kalapona) a i ʻole pūʻulu hydroxyalkyl, a laila hiki ke hoʻololi ʻia e nā hui hana ʻē aʻe e like me ka carboxyl, hydroxyl a i ʻole nā hui amino. Hoʻokahi, ʻelua a ʻoi aku paha nā ʻano mea pani. Ma ke kaulahao macromolecular cellulose, ua pani ʻia nā pūʻulu hydroxyl ma nā kūlana C(2), C(3) a me C(6) o kēlā me kēia ʻāpana glucose i nā ʻāpana like ʻole. ʻO ka ʻōlelo koʻikoʻi, ʻaʻohe ʻano kemika paʻa o ka cellulose ether, koe wale nā huahana i hoʻololi piha ʻia e kekahi ʻano hui (ua hoʻololi ʻia nā hui hydroxyl ʻekolu). Hiki ke hoʻohana ʻia kēia mau huahana no ka nānā ʻana a me ka noiʻi ʻana, a ʻaʻohe waiwai kūʻai.
(a) ʻO ke ʻano maʻamau o ʻelua ʻāpana anhydroglucose o ke kaulahao molekiko cellulose ether, R1~R6=H, a i ʻole kahi mea hoʻohui organik;
(b) He ʻāpana kaulahao molekula o carboxymethylhydroxyethyl cellulose, he 0.5 ka degere o ka hoololi ana i ka carboxymethyl, he 2.0 ka degere o ka hoololi ana o ka hydroxyethyl, a he 3.0 ka degere o ka hoololi ana i ka molar. Hōʻike kēia ʻano i ka pae hoʻololi maʻamau o nā pūʻulu etherified, akā ʻo nā mea hoʻololi maoli ʻia.
No kēlā me kēia mea pani, hōʻike ʻia ka nui o ka etherification e ka degere o ka waiwai DS pani. ʻO ka laulā o DS he 0 ~ 3, e like me ka helu awelika o nā pūʻulu hydroxyl i pani ʻia e nā hui etherification ma kēlā me kēia ʻāpana anhydroglucose.
No ka hydroxyalkyl cellulose ethers, e hoʻomaka ka hoʻololi ʻana i ka etherification mai nā hui hydroxyl manuahi hou, a hiki ke helu ʻia ke degere o ka hoʻololi ʻana e ka waiwai MS, ʻo ia hoʻi, ka degere molar o ka hoʻololi. Hōʻike ia i ka helu awelika o nā mole o ka mea etherifying agent reactant i hoʻohui ʻia i kēlā me kēia ʻāpana anhydroglucose. ʻO ka ethylene oxide ka mea hoʻoheheʻe maʻamau a he hydroxyethyl substituent ka huahana. Ma ke Kiʻi 1, ʻo ka waiwai MS o ka huahana he 3.0.
ʻO ka manaʻo, ʻaʻohe palena kiʻekiʻe no ka waiwai MS. Inā ʻike ʻia ka waiwai DS o ke degere o ka hoʻololi ʻana i kēlā me kēia pūʻulu apo glucose, ʻo ka awelika o ke kaulahao ʻaoʻao e hoʻohana pinepine kekahi mau mea hana i ka hakina nui (wt%) o nā hui etherification like ʻole (e like me -OCH3 a i ʻole -OC2H4OH) e hōʻike i ka pae hoʻololi a me ke degere ma mua o nā waiwai DS a me MS. Hiki ke hoʻololi ʻia ka hapa nui o kēlā me kēia hui a me kāna waiwai DS a i ʻole MS me ka helu maʻalahi.
ʻO ka hapa nui o nā eter cellulose he polymers hiki ke hoʻoheheʻe ʻia i ka wai, a he hapa hoʻi kekahi i hoʻoheheʻe ʻia i loko o nā mea hoʻoheheʻe organik. Loaʻa i ka cellulose ether nā hiʻohiʻona o ka hana kiʻekiʻe, ke kumukūʻai haʻahaʻa, ka hana maʻalahi, ka haʻahaʻa haʻahaʻa a me nā ʻano ākea ākea, a ke hoʻonui mau nei ka noi a me nā kahua noi. Ma ke ʻano he mea kōkua, ʻo ka cellulose ether ka mea hoʻohana nui i nā ʻano ʻoihana like ʻole. hiki ke loaʻa iā MS/DS.
Hoʻokaʻawale ʻia nā cellulose ethers e like me ke ʻano kemika o nā substituents i anionic, cationic a me nonionic ethers. Hiki ke hoʻokaʻawale ʻia nā ethers nonionic i ka wai-soluble a me ka aila.
Ua helu ʻia nā huahana i hana ʻia ma ka ʻaoʻao kiʻekiʻe o ka Papa 1. ʻO ka ʻaoʻao haʻahaʻa o ka Papa 1 ka papa inoa o kekahi mau hui etherification i ʻike ʻia, ʻaʻole i lilo i mau huahana kālepa koʻikoʻi.
Hiki ke kapa ʻia ka ʻōlelo pōkole o nā mea hoʻohui ether i hui ʻia e like me ke ʻano pīʻāpā a i ʻole ka pae o kēlā me kēia DS (MS), no ka laʻana, no ka 2-hydroxyethyl methylcellulose, ʻo HEMC ka pōkole, a hiki ke kākau ʻia ʻo MHEC i e kuhikuhi i ka methyl substituent.
ʻAʻole hiki ke maʻalahi nā pūʻulu hydroxyl ma cellulose e nā mea hana etherification, a ke hana mau ʻia ke kaʻina hana etherification ma lalo o nā kūlana alkaline, me ka hoʻohana maʻamau i kekahi ʻano o ka wai wai NaOH. Hoʻokumu mua ʻia ka cellulose i loko o ka cellulose alkali pehu me ka wai wai NaOH, a laila hoʻokō ʻia ka hopena etherification me ka mea hoʻoheheʻe etherification. I ka wā o ka hana ʻana a me ka hoʻomākaukau ʻana i nā ethers i hui pū ʻia, pono e hoʻohana ʻia nā ʻano ʻano etherification ʻokoʻa i ka manawa like, a i ʻole e hoʻokō ʻia ka etherification i kēlā me kēia pae ma ka hānai manawaleʻa (inā pono). ʻEhā ʻano ʻano pane i ka etherification o cellulose, i hōʻuluʻulu ʻia e ke ʻano pane (ua pani ʻia ka cellulosic e Cell-OH) penei:
Hōʻike ka hoʻohālikelike (1) i ka hopena etherification Williamson. ʻO RX he ester ʻakika inorganic, a ʻo X ka halogen Br, Cl a i ʻole sulfuric acid ester. Hoʻohana maʻamau ʻo Chloride R-Cl i ka ʻoihana, no ka laʻana, methyl chloride, ethyl chloride a i ʻole chloroacetic acid. Hoʻopau ʻia ka nui stoichiometric o ke kumu ma ia mau hopena. ʻO nā huahana cellulose ether industrialized methyl cellulose, ethyl cellulose a me carboxymethyl cellulose nā huahana o Williamson etherification reaction.
ʻO ke kumu hoʻohālikelike (2) ka hoʻohui ʻana o nā epoxide i hoʻopaʻa ʻia i ke kumu (e like me R=H, CH3, a i ʻole C2H5) a me nā pūʻulu hydroxyl ma nā molekole cellulose me ka ʻole o ka ʻai ʻana i ke kumu. Ke hoʻomau nei paha kēia hopena i ka hana ʻana o nā pūʻulu hydroxyl hou i ka wā o ka hopena, e alakaʻi ana i ka hoʻokumu ʻana o nā kaulahao ʻaoʻao oligoalkylethylene oxide: ʻO kahi hopena like me 1-aziridine (aziridine) e hana i ka aminoethyl ether: Cell-O-CH2-CH2-NH2 . ʻO nā huahana e like me hydroxyethyl cellulose, hydroxypropyl cellulose a me hydroxybutyl cellulose nā huahana āpau o ka base-catalyzed epoxidation.
ʻO ke ʻano hoʻohālikelike (3) ka pane ʻana ma waena o Cell-OH a me nā pūhui organik i loaʻa i nā mea paʻa pālua ikaika i loko o ke ʻano alkaline, ʻo Y he pūʻulu wehe electron, e like me CN, CONH2, a i ʻole SO3-Na+. I kēia mau lā, ʻaʻole hoʻohana ʻia kēia ʻano hana i ka ʻoihana.
ʻAʻole i hana ʻia ke ʻano hana pane (4), etherification me diazoalkane.
- Nā ʻano o ka cellulose ethers
Hiki i ka cellulose ether ke monoether a hui pū ʻia paha, a ʻokoʻa kona mau waiwai. Aia nā pūʻulu hydrophilic haʻahaʻa i hoʻololi ʻia ma ka macromolecule cellulose, e like me nā pūʻulu hydroxyethyl, hiki ke hāʻawi i ka huahana me kahi degere o ka wai solubility, ʻoiai no nā hui hydrophobic, e like me methyl, ethyl, etc. hāʻawi i ka huahana i kekahi wai hiki ke hoʻoheheʻe ʻia, a ʻo ka huahana haʻahaʻa i hoʻololi ʻia e pehu wale i ka wai a i ʻole hiki ke hoʻoheheʻe ʻia i loko o ka solution alkali dilute. Me ka noiʻi hohonu e pili ana i nā waiwai o cellulose ethers, e hoʻomau mau ʻia nā cellulose ethers hou a me kā lākou mau noi noi, a ʻo ka mea hoʻoikaika nui loa ka mākeke noiʻi ākea a hoʻomaʻamaʻa mau.
ʻO ke kānāwai maʻamau o ka mana o nā pūʻulu i loko o nā ethers i hui ʻia ma nā waiwai solubility:
1) Hoʻonui i ka ʻike o nā hui hydrophobic i ka huahana e hoʻonui i ka hydrophobicity o ka ether a hoʻohaʻahaʻa i ka helu gel;
2) Hoʻonui i ka ʻike o nā pūʻulu hydrophilic (e like me nā hui hydroxyethyl) e hoʻonui i kona kiko gel;
3) He mea kūikawā ka hui hydroxypropyl, a hiki i ka hydroxypropylation kūpono ke hoʻohaʻahaʻa i ka mahana gel o ka huahana, a piʻi hou ka mahana gel o ka huahana hydroxypropylated medium, akā ʻo kahi kiʻekiʻe o ka hoʻololi ʻana e hōʻemi i kona wahi gel; ʻO ke kumu ma muli o ka hana lōʻihi o ke kaulahao kalapona kūikawā o ka hui hydroxypropyl, hydroxypropylation haʻahaʻa, nāwaliwali nā paʻa hydrogen i loko a ma waena o nā molekala i loko o ka macromolecule cellulose, a me nā hui hydrophilic hydroxyl ma nā kaulahao lālā. Nui ka wai. Ma ka ʻaoʻao ʻē aʻe, inā kiʻekiʻe ka hoʻololi ʻana, aia ka polymerization ma ka pūʻulu ʻaoʻao, e emi ana ka pili o ka hui hydroxyl, e hoʻonui ka hydrophobicity, a e hoʻemi ʻia ka solubility.
Ka hana a me ka noiʻi ocellulose eterahe moʻolelo lōʻihi. I ka makahiki 1905, ua hōʻike mua ʻo Suida i ka etherification o cellulose, ka mea i methylated me ka dimethyl sulfate. Nonionic alkyl ethers ua patented e Lilienfeld (1912), Dreyfus (1914) a me Leuchs (1920) no ka wai-soluble cellulose ethers. Ua hana ʻo Buchler lāua ʻo Gomberg i ka benzyl cellulose i ka makahiki 1921, ua hana mua ʻia ka carboxymethyl cellulose e Jansen i ka makahiki 1918, a ua hana ʻo Hubert i ka hydroxyethyl cellulose i ka makahiki 1920. Mai 1937 a i 1938, ua hoʻokō ʻia ka hana ʻenehana o MC a me HEC ma United States. Ua hoʻomaka ʻo Suedena i ka hana ʻana i ka wai-soluble EHEC ma 1945. Ma hope o 1945, ua hoʻonui wikiwiki ʻia ka hana ʻana o ka cellulose ether ma Western Europe, ʻAmelika Hui Pū ʻIa a me Iapana. I ka hopena o 1957, ua hoʻokomo mua ʻia ʻo China CMC i ka hana ma Shanghai Celluloid Factory. Ma ka makahiki 2004, he 30,000 tons o ka ionic ether a me 10,000 tons o ka ether non-ionic ka nui o ko'u aina. Ma ka makahiki 2007, hiki i ka 100,000 tons o ka ionic ether a me 40,000 tons o ka Nonionic ether. Ke ulu mau nei nā ʻoihana ʻenehana hui ma ka home a ma waho, a ke hoʻomaikaʻi mau nei ka hana hana cellulose ether o Kina a me ka pae ʻenehana.
I nā makahiki i hala iho nei, ua hoʻomohala mau ʻia ka nui o nā cellulose monoethers a me nā ethers hui pū me nā waiwai DS like ʻole, viscosities, maʻemaʻe a me nā waiwai rheological. I kēia manawa, ʻo ka manaʻo o ka hoʻomohala ʻana i ke kula o ka cellulose ethers ʻo ia ka hoʻohana ʻana i ka ʻenehana hana kiʻekiʻe, ka ʻenehana hoʻomākaukau hou, nā lako hou, nā huahana hou, nā huahana kiʻekiʻe, a me nā huahana systematic pono e noiʻi ʻenehana.
Ka manawa hoʻouna: Apr-28-2024